Modelling a brick mortar masonry using periodic homogenisation and submodelling

To face coke and steel market requirement, the coking process has to be more flexible. But changing process parameters such as coking temperature and time, blend composition... can have consequences of the coke oven battery lifetime and on its masonries. The main objective of this work is to determine the admissible stress for the coke oven heating walls in order to prevent cracks formation. Thus a numerical tool of the coke oven battery based on the Finite Element Method was developed. It is a two-step model using homogenization and submodelling techniques in order to decrease the computational cost. Coke oven masonries are large structures composed of thousands of bricks and mortar joints. In the model, bricks and mortar are replaced by a Homogeneous Equivalent Material (HEM) whose behaviour depends on the joints state . The HEM properties are determined thanks to brick-mortar interface behaviour, experimentally characterised at high temperature. In order to control joint opening, a criterion changing the HEM is used. The use of the HEM gives the global stresses instead of local stresses, that's why, a submodelling step has been developed to obtain local stresses used in the criterion and thus to have accurate information about joint opening.